Interaction of Tat with Namalwa cell surface. (A) Flow cytometry profiles of Namalwa cells before or after treatment with Tat-GFP. (B) Namalwa cells were allowed to adhere to plastic coated with BSA or GST-Tat. Alternatively, SYN-NCs were allowed to adhere on plastic coated with GST-Tat (550 nM) for different periods of time (C), or for 2 hours in the presence of heparin, HS (29, 290 nM), unsulfated K5 polysaccharide (290 nM), or the indicated synthetic peptides of Tat (32 μM) (D). Then, adherent lymphocytes were counted. Each point is the mean ± SEM of 3 to 8 duplicate determinations. In panel D, data are expressed as percentage of adherent cells with respect to wells treated without competitors.